1. Field of the Invention
The present invention relates to a front fork of a saddle-ride-type vehicle.
2. Description of Background Art
A conventional front fork is known wherein a communication hole is formed in a casing portion which defines a gas chamber (volume compensation chamber) behind a free piston and oil in a cylinder body is released to a reservoir so that an increase in pressure in the cylinder body is avoided thus easily ensuring a predetermined gas spring force against the free piston. See, for example, JP-A-2005-30534.
The front fork described in JP-A-2005-30534 adopts the structure where oil in the cylinder body is discharged at a point in time wherein oil is compressed the most. Thus, a maximum compressed state appears during traveling at relatively low frequency or it is necessary to contract the front fork by applying a load to the front fork. Accordingly, it is difficult to provide the quantity of oil to an optimum oil quantity. Further, it is necessary to form a stepped portion on a casing portion and this formation of the stepped portion becomes a factor which pushes up the cost. Still further, the free piston adopts the structure where the piston includes two seals which are brought into slidable contact with an outer peripheral surface of the casing portion. Thus, a contact area of the seal portions with the outer peripheral surface of the casing portion is large whereby a friction is increased thus giving rise to a possibility that the seal portions adversely affect the operability of the free piston.